"""py.test fixtures

Fixtures for jupyterhub components
----------------------------------
- `app`
- `auth_state_enabled`
- `db`
- `io_loop`
- single user servers
    - `cleanup_after`: allows cleanup of single user servers between tests
- mocked service
    - `MockServiceSpawner`
    - `mockservice`: mocked service with no external service url
    - `mockservice_url`: mocked service with a url to test external services

Fixtures to add functionality or spawning behavior
--------------------------------------------------
- `admin_access`
- `no_patience`
- `slow_spawn`
- `never_spawn`
- `bad_spawn`
- `slow_bad_spawn`

"""
# Copyright (c) Jupyter Development Team.
# Distributed under the terms of the Modified BSD License.
import asyncio
import copy
import os
import sys
from getpass import getuser
from subprocess import TimeoutExpired
from unittest import mock

from pytest import fixture, raises
from tornado.httpclient import HTTPError
from tornado.platform.asyncio import AsyncIOMainLoop

import jupyterhub.services.service

from .. import crypto, orm, scopes
from ..roles import create_role, get_default_roles, mock_roles, update_roles
from ..utils import random_port
from . import mocking
from .mocking import MockHub
from .test_services import mockservice_cmd
from .utils import add_user

# global db session object
_db = None


@fixture(scope='module')
def ssl_tmpdir(tmpdir_factory):
    return tmpdir_factory.mktemp('ssl')


@fixture(scope='module')
async def app(request, io_loop, ssl_tmpdir):
    """Mock a jupyterhub app for testing"""
    mocked_app = None
    ssl_enabled = getattr(
        request.module, 'ssl_enabled', os.environ.get('SSL_ENABLED', False)
    )
    kwargs = dict()
    if ssl_enabled:
        kwargs.update(dict(internal_ssl=True, internal_certs_location=str(ssl_tmpdir)))

    mocked_app = MockHub.instance(**kwargs)

    def fin():
        # disconnect logging during cleanup because pytest closes captured FDs prematurely
        mocked_app.log.handlers = []
        MockHub.clear_instance()
        try:
            mocked_app.stop()
        except Exception as e:
            print("Error stopping Hub: %s" % e, file=sys.stderr)

    request.addfinalizer(fin)
    await mocked_app.initialize([])
    await mocked_app.start()
    return mocked_app


@fixture
def auth_state_enabled(app):
    app.authenticator.auth_state = {'who': 'cares'}
    app.authenticator.enable_auth_state = True
    ck = crypto.CryptKeeper.instance()
    before_keys = ck.keys
    ck.keys = [os.urandom(32)]
    try:
        yield
    finally:
        ck.keys = before_keys
        app.authenticator.enable_auth_state = False
        app.authenticator.auth_state = None


@fixture
def db():
    """Get a db session"""
    global _db
    if _db is None:
        # make sure some initial db contents are filled out
        # specifically, the 'default' jupyterhub oauth client
        app = MockHub(db_url='sqlite:///:memory:')
        app.init_db()
        _db = app.db
        for role in get_default_roles():
            create_role(_db, role)
        user = orm.User(name=getuser())
        _db.add(user)
        _db.commit()
    return _db


@fixture(scope='module')
def event_loop(request):
    """Same as pytest-asyncio.event_loop, but re-scoped to module-level"""
    event_loop = asyncio.new_event_loop()
    asyncio.set_event_loop(event_loop)
    return event_loop


@fixture(scope='module')
async def io_loop(event_loop, request):
    """Mostly obsolete fixture for tornado event loop

    Main purpose is to register cleanup (close) after we're done with the loop.
    The main reason to depend on this fixture is to ensure your cleanup
    happens before the io_loop is closed.
    """
    io_loop = AsyncIOMainLoop()
    assert asyncio.get_event_loop() is event_loop
    assert io_loop.asyncio_loop is event_loop

    def _close():
        io_loop.close(all_fds=True)

    request.addfinalizer(_close)
    return io_loop


@fixture(autouse=True)
async def cleanup_after(request, io_loop):
    """function-scoped fixture to shutdown user servers

    allows cleanup of servers between tests
    without having to launch a whole new app

    depends on io_loop to ensure it runs before things are closed.
    """

    try:
        yield
    finally:
        if _db is not None:
            # cleanup after failed transactions
            _db.rollback()

        if not MockHub.initialized():
            return
        app = MockHub.instance()
        if app.db_file.closed:
            return
        for uid, user in list(app.users.items()):
            for name, spawner in list(user.spawners.items()):
                if spawner.active:
                    try:
                        await app.proxy.delete_user(user, name)
                    except HTTPError:
                        pass
                    print(f"Stopping leftover server {spawner._log_name}")
                    await user.stop(name)
            if user.name not in {'admin', 'user'}:
                app.users.delete(uid)
        # delete groups
        for group in app.db.query(orm.Group):
            app.db.delete(group)
        app.db.commit()


_username_counter = 0


def new_username(prefix='testuser'):
    """Return a new unique username"""
    global _username_counter
    _username_counter += 1
    return f'{prefix}-{_username_counter}'


@fixture
def username():
    """allocate a temporary username

    unique each time the fixture is used
    """
    yield new_username()


@fixture
def user(app):
    """Fixture for creating a temporary user

    Each time the fixture is used, a new user is created
    """
    user = add_user(app.db, app, name=new_username())
    yield user


@fixture
def admin_user(app, username):
    """Fixture for creating a temporary admin user"""
    user = add_user(app.db, app, name=new_username('testadmin'), admin=True)
    yield user


_groupname_counter = 0


def new_group_name(prefix='testgroup'):
    """Return a new unique group name"""
    global _groupname_counter
    _groupname_counter += 1
    return f'{prefix}-{_groupname_counter}'


@fixture
def groupname():
    """allocate a temporary group name

    unique each time the fixture is used
    """
    yield new_group_name()


@fixture
def group(app):
    """Fixture for creating a temporary group

    Each time the fixture is used, a new group is created

    The group is deleted after the test
    """
    group = orm.Group(name=new_group_name())
    app.db.add(group)
    app.db.commit()
    yield group


class MockServiceSpawner(jupyterhub.services.service._ServiceSpawner):
    """mock services for testing.

    Shorter intervals, etc.
    """

    poll_interval = 1


_mock_service_counter = 0


async def _mockservice(request, app, external=False, url=False):
    """
    Add a service to the application

    Args:
        request: pytest request fixture
        app: MockHub application
        external (bool):
          If False (default), launch the service.
          Otherwise, consider it 'external,
          registering a service in the database,
          but don't start it.
        url (bool):
          If True, register the service at a URL
          (as opposed to headless, API-only).
    """
    global _mock_service_counter
    _mock_service_counter += 1
    name = 'mock-service-%i' % _mock_service_counter
    spec = {'name': name, 'command': mockservice_cmd, 'admin': True}
    if url:
        if app.internal_ssl:
            spec['url'] = 'https://127.0.0.1:%i' % random_port()
        else:
            spec['url'] = 'http://127.0.0.1:%i' % random_port()

    if external:
        spec['oauth_redirect_uri'] = 'http://127.0.0.1:%i' % random_port()

    event_loop = asyncio.get_running_loop()

    with mock.patch.object(
        jupyterhub.services.service, '_ServiceSpawner', MockServiceSpawner
    ):
        app.services = [spec]
        app.init_services()
        mock_roles(app, name, 'services')
        assert name in app._service_map
        service = app._service_map[name]
        token = service.orm.api_tokens[0]

        async def start():
            # wait for proxy to be updated before starting the service
            await app.proxy.add_all_services(app._service_map)
            await service.start()

        if not external:
            await start()

        def cleanup():
            if not external:
                event_loop.run_until_complete(service.stop())
            app.services[:] = []
            app._service_map.clear()

        request.addfinalizer(cleanup)
        # ensure process finishes starting
        if not external:
            with raises(TimeoutExpired):
                service.proc.wait(1)
        if url:
            await service.server.wait_up(http=True)
    return service


@fixture
async def mockservice(request, app):
    """Mock a service with no external service url"""
    yield await _mockservice(request, app, url=False)


@fixture
async def mockservice_external(request, app):
    """Mock an externally managed service (don't start anything)"""
    yield await _mockservice(request, app, external=True, url=False)


@fixture
async def mockservice_url(request, app):
    """Mock a service with its own url to test external services"""
    yield await _mockservice(request, app, url=True)


@fixture
def admin_access(app):
    """Grant admin-access with this fixture"""
    with mock.patch.dict(app.tornado_settings, {'admin_access': True}):
        yield


@fixture
def no_patience(app):
    """Set slow-spawning timeouts to zero"""
    with mock.patch.dict(
        app.tornado_settings, {'slow_spawn_timeout': 0.1, 'slow_stop_timeout': 0.1}
    ):
        yield


@fixture
def slow_spawn(app):
    """Fixture enabling SlowSpawner"""
    with mock.patch.dict(app.tornado_settings, {'spawner_class': mocking.SlowSpawner}):
        yield


@fixture
def full_spawn(app):
    """Fixture enabling full instrumented server via InstrumentedSpawner"""
    with mock.patch.dict(
        app.tornado_settings, {'spawner_class': mocking.InstrumentedSpawner}
    ):
        yield


@fixture
def never_spawn(app):
    """Fixture enabling NeverSpawner"""
    with mock.patch.dict(app.tornado_settings, {'spawner_class': mocking.NeverSpawner}):
        yield


@fixture
def bad_spawn(app):
    """Fixture enabling BadSpawner"""
    with mock.patch.dict(app.tornado_settings, {'spawner_class': mocking.BadSpawner}):
        yield


@fixture
def slow_bad_spawn(app):
    """Fixture enabling SlowBadSpawner"""
    with mock.patch.dict(
        app.tornado_settings, {'spawner_class': mocking.SlowBadSpawner}
    ):
        yield


@fixture
def create_temp_role(app):
    """Generate a temporary role with certain scopes.
    Convenience function that provides setup, database handling and teardown"""
    temp_roles = []
    index = [1]

    def temp_role_creator(scopes, role_name=None):
        if not role_name:
            role_name = f'temp_role_{index[0]}'
            index[0] += 1
        temp_role = orm.Role(name=role_name, scopes=list(scopes))
        temp_roles.append(temp_role)
        app.db.add(temp_role)
        app.db.commit()
        return temp_role

    yield temp_role_creator
    for role in temp_roles:
        app.db.delete(role)
    app.db.commit()


@fixture
def create_user_with_scopes(app, create_temp_role):
    """Generate a temporary user with specific scopes.
    Convenience function that provides setup, database handling and teardown"""
    temp_users = []
    counter = 0
    get_role = create_temp_role

    def temp_user_creator(*scopes, name=None):
        nonlocal counter
        if name is None:
            counter += 1
            name = f"temp_user_{counter}"
        role = get_role(scopes)
        orm_user = orm.User(name=name)
        app.db.add(orm_user)
        app.db.commit()
        temp_users.append(orm_user)
        update_roles(app.db, orm_user, roles=[role.name])
        return app.users[orm_user.id]

    yield temp_user_creator
    for user in temp_users:
        app.users.delete(user)


@fixture
def create_service_with_scopes(app, create_temp_role):
    """Generate a temporary service with specific scopes.
    Convenience function that provides setup, database handling and teardown"""
    temp_service = []
    counter = 0
    role_function = create_temp_role

    def temp_service_creator(*scopes, name=None):
        nonlocal counter
        if name is None:
            counter += 1
            name = f"temp_service_{counter}"
        role = role_function(scopes)
        app.services.append({'name': name})
        app.init_services()
        orm_service = orm.Service.find(app.db, name)
        app.db.commit()
        update_roles(app.db, orm_service, roles=[role.name])
        return orm_service

    yield temp_service_creator
    for service in temp_service:
        app.db.delete(service)
    app.db.commit()


@fixture
def preserve_scopes():
    """Revert any custom scopes after test"""
    scope_definitions = copy.deepcopy(scopes.scope_definitions)
    yield scope_definitions
    scopes.scope_definitions = scope_definitions
